A number of endovascular procedures are presently performed on patients with atherosclerotic disease and the like to treat stenotic or occluded regions within the patient's blood vessels, such as the coronary, carotid or cerebral arteries. For example, an angioplasty procedure may be used to dilate a stenosis, or an atherectomy may be performed to open severely occluded regions. A stent or other prosthesis may be implanted to retain patency of a vessel, either alone or in conjunction with these procedures.
One of the problems with these procedures, however, is that embolic material may be released from the wall of the vessel during the procedure, and travel downstream where it may become lodged or otherwise cause harm to the patient. For example, ischemic stroke may occur when such emboli are released in the carotid or cerebral arteries and travel to the patient's brain.
To prevent or minimize damage from emboli, vascular filters have been suggested that are generally mounted on a device, such as a catheter, a guidewire, or a sheath. These devices may be introduced within a blood vessel downstream of a location being treated, and the filter on the device deployed across the vessel to capture embolic material released during a procedure, such as one of the procedures above. Upon completion of the procedure, the filter is collapsed, and the device removed from the patient.
These filter devices are generally introduced endoluminally over a rail, such as a guidewire, that is also used subsequently to introduce one or more surgical tools or other devices used to perform the procedure. During the advancement of these subsequent devices, the rail may be pushed and pulled axially within the vessel, causing the deployed filter to move back and forth. This movement of the filter may damage the vessel intima, may release embolic material captured by the filter, and/or may damage the structure of the filter itself.
Implantable filter devices have also been suggested that may be deployed, expanded and released within vessels, such as vena cava filters. These filter devices may not recovered, or may remain within the vessel for extended periods of time, where they may eventually become obstructed with thromboses, clots, emboli and the like, and harm the patient.
Therefore, there is a need for a vascular filter that may be deployed to capture embolic material with minimal risk of damage to the vessel and patient and/or that may be may be more easily recovered from the patient.